Installing mods or custom WAD (Where's All the Data?) files in the original 1993 version of Doom can significantly enhance and personalize your gameplay experience. These WAD files can include custom levels, graphics, sounds, and gameplay mechanics. Here is a step-by-step guide to add and play custom levels and modifications in Doom: 1. **Locate your Doom installation:** Make sure you know the folder where Doom is installed. This is where you will place the custom WAD files. 2. **Download Custom WADs:** Find custom WAD files you want to play. Websites like Doomworld's /idgames database are great places to start. Make sure to download WADs that are compatible with the version of Doom you are playing. 3. **Installing a Source Port (Optional, but recommended):** While you can use the original 'DOOM.EXE' to play custom WADs, many modern players prefer using a source port for better compatibility and additional features. A source port is an engine that has been updated to run on modern systems with various improvements. Popular source ports for Doom include GZDoom, Chocolate Doom, and PRBoom+. 4. **Copy the WAD files:** Place the downloaded WAD files into the same directory as your Doom executable file (or as specified by the source port you're using). 5. **Load the WAD file:** The method to load the WAD file can vary depending on whether you're using the original engine or a source port. - **Using the original DOOM.EXE:** You can use the `-file` command-line parameter to load the WAD. For example, if you want to load a file named 'MYLEVEL.WAD', you would navigate to your Doom directory in the command prompt and type: ``` DOOM -file MYLEVEL.WAD ``` - **Using a Source Port:** Most source ports provide a more user-friendly way to load WAD files, often allowing you to drag-and-drop the WAD file onto the executable or use a built-in graphical user interface (GUI) launcher where you can specify which WADs to load. 6. **Launching the Game:** After loading the WAD file, launch the game. If everything is done correctly, the game will start with the mod's custom content. 7. **Troubleshooting:** If the mod doesn't work, check the following: - Ensure that the WAD is designed for the version of Doom you're playing (Doom, Doom II, etc.). - Check if the WAD requires a specific source port to run. - Read the documentation that comes with the WAD for any special instructions. Remember to respect the rights and licenses attached to mods and custom content. Many mod authors only grant permission for personal use and prohibit redistribution without their consent. Always give credit when discussing or sharing mods created by the Doom community.